Allow MediaSession in iframes to be routed

content/browser/media/session/media_session_player_observer.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_PLAYER_OBSERVER_H_
 #define CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_PLAYER_OBSERVER_H_
 
 namespace content {
 
+class RenderFrameHost;
+
 class MediaSessionPlayerObserver {
  public:
   MediaSessionPlayerObserver() = default;
   virtual ~MediaSessionPlayerObserver() = default;
 
   // The given |player_id| has been suspended by the MediaSession.
   virtual void OnSuspend(int player_id) = 0;
 
   // The given |player_id| has been resumed by the MediaSession.
   virtual void OnResume(int player_id) = 0;
 
   // The given |player_id| has been set a new volume multiplier by
   // the MediaSession.
   virtual void OnSetVolumeMultiplier(int player_id,
                                      double volume_multiplier) = 0;
+
+  // Returns the RenderFrameHost this player observer belongs to. Returns
+  // nullptr if unavailable.
+  virtual RenderFrameHost* GetRenderFrameHost() const = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_PLAYER_OBSERVER_H_